The present invention relates to a virtual machine system, and more particularly to a technique for presetting a pattern for dynamically changing a virtual machine to perform a change pattern by a predetermined trigger in a server virtual environment.
A server virtualization technology has been widely used for allocating a resource of a physical computer to a plurality of virtual servers (hereinafter referred to as a virtual computer) and logical partitions (hereinafter referred to as an LPAR) in such a way that one physical computer provides a plurality of virtual computers. It is possible to run a virtual computer with flexibility for a dynamic change in a resource to be allocated, hot migration for migrating a virtual computer being operated to the other physical computer, and the like (see Japanese Patent Application Laid-open No. 2008-217302, for example).
In a computer system applying the server virtual technique (hereinafter referred to as a server virtual environment), it is possible to combine a dynamical change in a resource, hot migration and the like for improving availability of a virtual computer, and improving load-leveling and scalability of a physical computer. For such a dynamic change of a virtual computer, an administrator of a computer system or the like presets, based on an operating policy and the like, a combination of a change in a resource, hot migration and the like, a trigger for execution and the like, as control patterns. Triggers for execution include occurrence of a failure, the value of usage or a remaining amount of resources and a significant increase in a load of a physical computer.